btrfs: print-tree: debugging output enhancement

This patch enhances the following things:

- tree block header
* add generation and owner output for node and leaf
- node pointer generation output
- allow btrfs_print_tree() to not follow nodes
* just like btrfs-progs

Please note that, although function btrfs_print_tree() is not called by
anyone right now, it's still a pretty useful function to debug kernel.
So that function is still kept for later use.

Signed-off-by: Qu Wenruo <[e-mail]>
Reviewed-by: Lu Fengqi <[e-mail]>
Signed-off-by: David Sterba <[e-mail]>

fs/btrfs/print-tree.c

···
 	fs_info = l->fs_info;
 	nr = btrfs_header_nritems(l);
 
-	btrfs_info(fs_info, "leaf %llu total ptrs %d free space %d",
-		   btrfs_header_bytenr(l), nr,
-		   btrfs_leaf_free_space(fs_info, l));
+	btrfs_info(fs_info,
+		   "leaf %llu gen %llu total ptrs %d free space %d owner %llu",
+		   btrfs_header_bytenr(l), btrfs_header_generation(l), nr,
+		   btrfs_leaf_free_space(fs_info, l), btrfs_header_owner(l));
 	for (i = 0 ; i < nr ; i++) {
 		item = btrfs_item_nr(i);
 		btrfs_item_key_to_cpu(l, &key, i);
···
 	}
 }
 
-void btrfs_print_tree(struct extent_buffer *c)
+void btrfs_print_tree(struct extent_buffer *c, bool follow)
 {
 	struct btrfs_fs_info *fs_info;
 	int i; u32 nr;
···
 		return;
 	}
 	btrfs_info(fs_info,
-		   "node %llu level %d total ptrs %d free spc %u",
-		   btrfs_header_bytenr(c), level, nr,
-		   (u32)BTRFS_NODEPTRS_PER_BLOCK(fs_info) - nr);
+		   "node %llu level %d gen %llu total ptrs %d free spc %u owner %llu",
+		   btrfs_header_bytenr(c), level, btrfs_header_generation(c),
+		   nr, (u32)BTRFS_NODEPTRS_PER_BLOCK(fs_info) - nr,
+		   btrfs_header_owner(c));
 	for (i = 0; i < nr; i++) {
 		btrfs_node_key_to_cpu(c, &key, i);
-		pr_info("\tkey %d (%llu %u %llu) block %llu\n",
+		pr_info("\tkey %d (%llu %u %llu) block %llu gen %llu\n",
 		       i, key.objectid, key.type, key.offset,
-		       btrfs_node_blockptr(c, i));
+		       btrfs_node_blockptr(c, i),
+		       btrfs_node_ptr_generation(c, i));
 	}
+	if (!follow)
+		return;
 	for (i = 0; i < nr; i++) {
 		struct btrfs_key first_key;
 		struct extent_buffer *next;
···
 		if (btrfs_header_level(next) !=
 		       level - 1)
 			BUG();
-		btrfs_print_tree(next);
+		btrfs_print_tree(next, follow);
 		free_extent_buffer(next);
 	}
 }

fs/btrfs/print-tree.h

···
 #define BTRFS_PRINT_TREE_H
 
 void btrfs_print_leaf(struct extent_buffer *l);
-void btrfs_print_tree(struct extent_buffer *c);
+void btrfs_print_tree(struct extent_buffer *c, bool follow);
 
 #endif